An in vitro investigation into the wear effects of glazed, unglazed and refinished dental porcelain on an opposing material

Abstract

A machine designed to simulate the physical parameters of masticatory function was used to investigate the amount of wear produced on perspex plates opposing discs of porcelain which were glazed, unglazed or finished to varying stages of a polishing sequence recommended with a proprietary finishing kit. The perspex specimens were abraded, under water at 37 degrees C for a total of 800000 contacts using a contact time of 0.2 s, a sliding distance of 15 mm and a constant load of 0.19 N/mm2. Assessments of the wear of the perspex were based upon depth measurements of the wear track recorded on surfometric tracings. Further measurements of the cross-sectional area of the wear track were made using an image analysing computer. The investigation confirmed that the best finish and least abrasive surface was produced by glazing of porcelain. The finish produced by intermediate components of the proprietary finishing kit did not reduce the abrasiveness of the porcelain surface. It was necessary to complete the polishing sequence with diamond paste to achieve a surface which approached the wear characteristics of glazed porcelain. It is recommended that any adjusted porcelain restoration should be re-glazed or subjected to a finishing sequence which is followed through to a final stage of polishing with a diamond paste.

Effects of surface-finishing protocols on the roughness, color change, and translucency of different ceramic systems

“…PK or DP methods created Ra comparable to that of the glazed specimens, which is in line with previous observations. 4,8,10 Various finishing and polishing protocols could be employed on ceramic surfaces to preserve the structural resistance and obtain a clinically acceptable smoothness compared with glazing. 4,6,[8][9][10] In this context, it seems that diamond pastes are efficient in decreasing the irregularities on ceramics, when used after the adjustment burs.…”

“…3 Natural glaze is a vitrified porcelain layer that forms on the surface of the porcelain, containing a glass phase when the porcelain is heated to the glazing temperature for the specified time according to the manusfacturer. 4 This layer may be deteriorated by clinical adjustment of the final restoration resulting in rough surface resembling a pretreated surface texture. [4][5][6][7] Polishing have been shown to improve structural resistance to withstand oral conditions, and ensure optical characteristics of the restoration.…”

“…4 This layer may be deteriorated by clinical adjustment of the final restoration resulting in rough surface resembling a pretreated surface texture. [4][5][6][7] Polishing have been shown to improve structural resistance to withstand oral conditions, and ensure optical characteristics of the restoration. [8][9][10] Mismatch of translucency and color of the core and veneering system in a ceramic system with that of natural enamel that has inherent translucency can be considered a failure.…”

Feldspati̇k Ve Li̇tyum Di̇si̇li̇kat Cam Porselenleri̇n Yüzey Pürüzlülüğü Üzeri̇nde Farkli Yüzey İşlemleri̇ni̇n Etki̇si̇ni̇n İncelenmesi̇

“…Yine bu işlemler sıra-sında porselen yüzeyinde mikro yivler oluşturularak pürüzlü ve düzensiz oluşumlar meydana gelir. 4 Bu şekilde oluşturulan pürüzlü yüzeyler, alınan gıda pigmentlerinin mekanik retansiyonlarını ve ağızda var olan bakterilerin adezyonlarını sağlar. Bu da plak formasyonlarını hızlandırarak dişeti enflamasyonları ve dişlerin çürüme risklerini arttırır.…”

“…21 Bu yüzden farklı yüzey bitirme tekniklerinden sonra, porselenlerde oluşan yüzey pürüzlülükleri, protez uzmanlarının üzerinde yoğun-laştıkları bir konu olmuştur. 4 IPS Empress 2 yapısal olarak farklı lityum disilikat ve fluorapatit kristallerinin birleşmesinden oluşur. Bu yapı sayesinde kırılmalara karşı daha büyük direnç, karşı dişlerde daha az aşınma ve mükemmel estetik sağlarlar.…”